New Tax Credit for Other Dependents
Beginning with the 2018 tax return, you can claim a $500 non-refundable credit for each eligible dependent for whom the child tax credit cannot be claimed. It is figured on the same worksheet (Child Tax Credit and Credit for Other Dependents Worksheet).
This is the list of those that might be eligible for this new credit:
Your qualifying relative (must be a US citizen, US National, or US Resident Alien and has a Social Security Number or an ITIN or ATIN that is issued before the due date of the 2018 return including extensions). If you apply for one of these prior to filing your return it is considered as having obtained them.
Your dependent child who is 17 or over by the end of 2018 and can no longer be eligible for the child tax credit.
Your qualifying child who is under age 17 at the end of 2018 but did not have a Social Security number valid for employment issued before the date of your tax return. Therefore you can use the credit for other dependents rather than the child care credit.
There are phase out rules for this credit as well as the child care credit.